Highly absorbent bonded nonwoven fabrics

ABSTRACT

THE PRESENT INVENTION IS CONCERNED WITH NEW AND IMPROVED BINDERS FOR THE PRODUCTION OF NONWOVEN FABRICS WHICH HAVE A HIGH DEGREE OF ABSORBENCY, AND RETAIN THEIR BONDED CHARACTER AS WELL AS ABSORBENCY THROUGH NUMEROUS WASH-DRY CYCLES. THE FABRICS ARE BONDED BY A NOVEL SELFCROSSLINKING BINDER COMPRISING A COPOLYMER OF (A) NMETHYLOLAMINE OR -AMIDE UNITS, (B) SULFONIC ACID UNITS WHICH CONTAIN NO BASIC NITROGEN ATOMS OR GROUP, AND (C) CERTAIN ACRYLIC UNITS OF NEUTRAL BUT MILDLY HYDROPHILIC CHARACTER WHICH CONTAIN NO BASIC NITROGEN ATOMS OR GROUP.

United States Patent C) 3,705,053 HIGHLY ABSORBENT BONDED NONWOVENFABRICS William D. Emmons, Huntingdon Valley, Vincent J. Moser,Abington, John G. Brodnyan, Langhorne, and Norman Shachat, Levittown,Pa., assignors to Rohm and Haas Company, Philadelphia, Pa. No Drawing.Filed Apr. 16, 1971, Ser. No. 134,904 Int. Cl. D611 3/04; B32b 27/12U.S. Cl. 117140 A 4 Claims ABSTRACT OF THE DISCLOSURE The presentinvention is concerned with new and improved binders for the productionof nonwoven fabrics which have a high degree of absorbency, and retaintheir bonded character as well as absorbency through numerous wash-drycycles. The fabrics are bonded by a novel self crosslinking bindercomprising a copolymer of (a) N- methylolamine or -amide units, (b)sulfonic acid units which contain no basic nitrogen atoms or group, and(c) certain acrylic units of neutral but mildly hydrophilic characterwhich contain no basic nitrogen atoms or group.

It is already known to use N-methylol-acrylamide in copolymers to beused for bonding nonwoven fabrics and setting the binder in the fabricby heating the fabric impregnated therewith with a suitable acidcatalyst to accelerate the crosslinking of the binder to insolublecondition on the fabric. When this is done, however, the bonded fabricgenerally becomes markedly less readily wettable than the fibrous massthat is used in making the bonded fabric. Hence, there is an undesirablewater-repellency in the bonded mass which makes it relatively unsuitablefor use as a wiping cloth or rag to remove and pick up liquids, as inwashing furniture, as in kitchens in the home, or in washing cars.

Attempts have been made to overcome this disadvantage by selection ofsurfactant in the emulsion polymerization of the monomers to produce thebinder and by the addition of a wetting agent to the impregnating mediumby which the binder is applied to the nonwoven fabric. However, suchexpedients interfere with the removal of aqueous liquids when suchfabrics are used for wiping wet surfaces, cause smearing of the liquidover the surface, and, in most instances, serve for one time use onlybecause the surfactant or wetting agent is removed during the first use.

In accordance with the present invention, a binder copolymer itself ismodified to incorporate a component which provides improved absorbencyand at the same time remains in the binder so that it is not removedduring use, rinsing, or washing of the cellular article or nonwovenfabric. The binder copolymer comprises a component (a), namely anN-methylolor N-alkoxymethyl-substituted nitrogen-containingmonoethylenically unsaturated monomer which imparts thermosettingqualities to the copolymer and may also serve to chemically bond thebinder to the fibers of a nonwoven fabric. The binder also comprises acomponent (b) namely, an a,[3-unsaturated monomer, which iscopolymerizable with the nitrogen-containing monomer, contains a strongsulfur acid group having a pKa of 3.5 or less, but contains no basicnitrogen atom or group. This component serves to impart absorbency andrewettability. The balance (component (c)) of the binder copolymer, tomake 100% by weight, may comprise one or more other a,/3-ethylenicallyunsaturated monomers which contain no basic nitrogen atom or group andare at the most only moderately hydrophobic so that this component doesnot overcome the hydrophilicity of the secondmentioned component andthereby cause excessive reduction of absorbent and wettablecharacteristics.

By basic nitrogen atom, it is intended to refer to the nitrogen atom inan ordinary amine group (primary, secondary, or tertiary). Such groupsare normally basic in character. This definition excludes the nitrogenatom of a carboxylic acid amide group and that of a ureido or carbamidegroup.

For the first component there may be used various monomers containing anitrogen atom substituted with at least one methylol or methoxymethylgroup. More specifically, the monomer that is useful here contains acarboxamido group, a ureido group, or an amino group in which thenitrogen atom is attached to a carbon atom in the ring of a1,3,5-triazine. The nitrogen of the carboxamido, ureido or amino groupis methylolated to attach at least one methylol group to the nitrogenatom, and, if desired, the N-methylol derivative is converted to thecorresponding N-methoxymethyl-substituted derivative, all inconventional manner. Examples of monomers containing carboxamido groupsare those derivatives of the amides of monoethylenically unsaturatedmonocarboxylic and dicarboxylic acids having a group of the formula H @Csuch as the N-methyloland N-methoxymethyl-substituted derivativesobtained from acrylamide, methacrylamide, maleimide, maleamic acid,itaconamic acid, crotonamide, fumarimide, fumaramic acid,acryloxypropionamide, and so on. Of these, the preferred monomers arethose having a terminal group of the formula H C C such as acrylamideand methacrylamide.

N-methylolated or N-methoxymethyl derivatives of ethylenicallyunsaturated monomers containing ureido groups are also useful. Examplesof such ureido monomers are:

Compounds of the formula A is an alkylene group having 2 to 8 carbonatoms,

R is selected from the group consisting of H, alkyl groups having 1 to 4carbon atoms, hydroxyalkyl groups having 1 to 4 carbon atoms, andalkoxymethyl groups having 2 to 5 carbon atoms,

X is oxygen or sulfur,

R when not directly attached to R is H, phenyl, methylbenzyl, benzyl,cyclohexyl or alkyl having 1 to 6 carbon atoms, hydroxyalkyl having 1 to6 carbon atoms, N-alkoxyalkyl having 2 to 6 carbon atoms; R when notdirectly attached to R, is H, phenyl, methylbenzyl, benzyl, cyclohexylor alkyl having 1 to 6 carbon atoms, and R and R when directly connectedtogether, may be the morpholino residue -C H OC H the piperidino residueor the pyrrolidino residue -(CH at least one of R, R and R beingmethylol or methoxymethyl.

Examples of these compounds include:

N-methylol-B-ureidoethyl vinyl ether, N-met'hylol-fi-ureidoethyl vinylsulfide, N-methylol-p-thioureidoethyl vinyl ether,

3 N-methylol-B-thioureidoethyl vinyl sulfide, N-methylol-p-ureidoethylacrylate, N-methylol-B-thioureidoethyl methacrylate, N-methylol-N'-B-ureidoethyl acrylamide, N-methylol-N- fl-ureido ethyl) methacrylamide,N-methylol N-,B-methacryloxyethyl-urea,N-methylol-N'-methylol-N'-{3-acryloxyethyl-urea,N-methoxymethyl-N-B-viuyloxyethyl-urea.

Among the ureido-containing monomers, those containing a cyclic ureidogroup of the following Formula II are also quite useful.

)"C (I wherein A and X are as defined hereinbefore. The preferred cyclicureido compounds are those which contain the group (III) which may betermed the cyclic N,N'-ethyleneureido group.

In II or III, one of the nitrogen atoms is connected to a polymerizablemonoethylenically unsaturated radical and the substituent on the othernitrogen may be methylo] or methoxymethyl.

Many other monoethylenically unsaturated monomers contain cyclic ureidogroups and are useful for producing component (a) of the copolymerinvention. Compounds of the following formulas wherein Y represents thegroup of Formula II above and R is methylol or methoxymethyl aretypical:

H C=CHYR (IV) H C=CHXAYR (V) wherein X and A are as defined hereinabove.

o HZC=C(R) iiZAYR (VI) where R is selected from the group consisting ofH and CH Z is selected from the group consisting of O- and NR R beingselected from the group consisting of H, cyclohexyl, benzyl, and analkyl group having 1 to 6 carbon atoms, and A is as defined hereinabove.

O HzC=C(R) QENR CHZYR (VII) wherein R, Y, and R are as definedhereinabove and R is H or alkyl having 1 to 12 carbon atoms;

i (VIII-A) wherein A, X and 'R are as defined hereinabove.

4 The N-substituted amic acid and esters derived from maleamic acid aretypical and have the following generic formula in which A, R and X areas defined hereinabove, and R is an alkyl group having 1 to 12,preferably 1 to 4, carbon atoms. The internal cyclic imides derived frommaleamic acid that are useful herein have the formula The unsaturateddicarboxylic acid monoesters of a compound of the formula i (XI) whereinA is a (C -C )alkylene group, n is an integer having a value of l to 4,and A and R are as defined hereinbefore, derived from maleic, fumaric,chloromaleic, itaconic or citraconic acid. There may also be used thebenzyl, cyclohexyl, and (C C )alkyl esters of any of the monoesters justdescribed which are disclosed in U.S. Pat. 3,194,792, and the specificcompounds disclosed therein are incorporated herein by reference.Specific examples include:

Methylolated B- (N,N-ethyleneureido)ethyl acid maleate,

Methylolated p (N,N'-ethyleneureido)ethyl acid fumarate,

Methylolated methyl 8-(N,N-ethyleneureido)ethyl fumarate,

Methylolated ,8-(N,N'-ethyleneureido)ethyl fumarate.

Additional illustrative examples of carboxamide type include those of'U..S. Pat. 3,274,164 having the general formula wherein R is selectedfrom the group consisting of H and alkyl having 1 to 18 carbon atoms,and n is a number having an average value of about 0.8 to 2.0 andpreferably having an average value of about 1.

Specific examples of the compounds represented by the several FormulasIII to XII given above include:

(A) Formulas III and IV N-vinyl-N'-methylol-N,N'-ethyleneureaN-vinyl-N'-methoxymethyl-N,N-ethyleneurea (B) Formula VN-vinyloxyethyl-N-methylol-N,N-ethyleneureaN-vinyloxyethyl-N-methoxymethyl-N,N-ethyleneureaN-vinylthioethy1-N'-methylol-N,N'-ethyleneurea.

(C) Formula VI N- (B-methacrylamidoethyl) -N'-methylol-N,N'-

ethyleneurea N-(fl-acrylamidoethyl)-N'-methoxymethyl-N,N-

ethyleneurea N-(fl-acryloxyethyl)-N'-methylol-N,N'-ethyleneurea N-p-methacryloxypropyl -N'-methylol-N,N'-

propyleneurea (XII) N-(fi-acryloxyethyl)-N'-methoxymethyl-N,N'-

ethyleneurea N-(,B-acryloxyethyl)N-methylol-N,N-ethylenethiourea (D)Formula VII N-acrylamidomethyl-N'-methylol-N,N-ethyleneureaN-acrylamidomethyl-N'-methylol-N,N'-propyleneurea (E) Formula VIII N-[fi-(a-acryloxyacetamido)ethyl]-N'-methylol- N,N'-ethyleneurea N-flu-methacryloxyacetamido ethyl] -N'-methylol- N,-N-ethylenethiourea N-[[3- a-methacryloxyacetamido )ethyl] -N-methylol- N ,N'-ethyleneurea (F)Formulas IX, X, XI, and related compounds from other unsaturateddicarboxylic acids N- [fl-(B-carboxyacrylamido)ethyl]-N'-methylol-N,N-ethyleneurea N- [B-(B-carbomethoxyacrylamido)ethyl]-N'-methoxymethyl-N,N'-ethyleneurea N-[fl-(B-(ethylcarbonyl)acrylamido)ethyl]-N-methylol- N,N'-ethyleneureaN-[fi-(fi-carbomethoxyacrylamido )propyl]-N'- methylol-N,N-propyleneureaN- [fi-(B-(methylcarbonyl)acrylamido)ethyl]-N'-methoxymethyl-N,N'-ethyleneurea.

Methylolated 1-[2-(fl-trans-carbomethoxyacrylamido)-ethylJ-imidazolidinone-Z (see Ex. 5 of 2,986,652).

(G) Formula XII The most useful of these compounds are N-methylolandM-methoxymethyl-4-pentenamide.

N-methylolor N-methoxymethyl-substituted aminotriazines in which thethus-substituted amino group is attached to a carbon atom of a1,3,5-triazine ring containing an ethylenically unsaturated substituenthaving a group H C=C can also be used as component (a) of the copolymer.They may have the general formula n is 0 or 1,

R is selected from the group consisting of H, CH OH,

and CH OCH R is selected from the group consisting of H, CH OH,

and CH OOH I R is selected from the group consisting of H, CH OH,

and CH OCH R is selected from the group consisting of H, CI-I OH, and CHCH at least one of R", R R and R being methylol or methoxymethyl, and

R is an alkenyl group having 2 to 9 carbon atoms and a terminal group HC=C In other terms, the group R is an alkenyl group of the formula C Hin which n. has a value of 2 to 9, which alkenyl group has a terminalgroup H C:C Examples in which n is zero includeN-methylolacryloguanamine, N-methoxymethylacryloguanamine, N-methylol 3butyroguanamine, and N-methylol-methacryloguanamine. When n is 1 and Rhas at least 3 carbon atoms, especially valuable monomers are embracedby the formula in which the double bond of the side chain substituent isin nonconjugated relationship in respect to the double bonds of thering. Examples are N-methylolor N- methoxymethyl-4-pentenoguanamine andthe related compounds disclosed in US. Pat. 3,446,777.

Generally, it is undesirable to include in the copolymers of the presentinvention an amino compound that is moderately or strongly basic incharacter. However, the monomers which contain an amino group, thenitrogen atom of which is attached directly to a carbon atom in the ringof a 1,3,5-triazine is only weakly basic and does not interfere with themeritorious qualities of the resulting copolymers.

The amount of N-methylolor N-methoxymethyl-substituted monomericmaterial required in the binder copolymer may be as low as about 0.2% byweight based on the Weight of the copolymer, or it may be as high asabout 10% by weight. Preferred copolymers contain about 0.5 to 4% byweight of such a monomer or mix- 5 ture thereof.

The second component of the binder copolymer may also be derived from awide range of monomers. Examples include ethylenesulfonic acid(vinylsulfonic acid), allylsulfonic acid, methallylsulfonic acid,2-acrylamido-2- methylpnopanesulfonic acid, 2-acrylamido 2methylbutane-3-sulfonic acid, and the unsaturated aromatic sulfonicacids of US. Pat. 2,527,300, especially those of the formula SOaHwherein R is hydrogen, methyl, or a halogen,

X is an alkyl group containing from 1 to 4 carbon atoms or a halogenatom,

n is zero or a whole number from 1 to 3, and the total number of carbonatoms in (X) is not over 4.

Also useful are the sulfo-esters of tat-methylene carboxylic acids ofUS. Pat. 3,024,221 or of US. Pat. 2,964,557 having the following formulawherein the symbol R represents hydrogen, a halogen such as chlorine, oran organic radical such as an alkyl radical, the symbol Q- represents abivalent organic radical having 2 to 10 carbon atoms and having itsvalence bonds on two dilferent carbon atoms, such as an alkylene orarylene radical, and M is a member of the group consisting of hydrogen,ammonium bases, and metals. The term sulfo ester of an rat-methylenecarboxylic acid is used herein to mean an ester corresponding to acarboxylate ester of an tat-methylene carboxylic acid and a hydroxyorganic compound, which latter compound has, as substituent on a carbonatom thereof, a sulfo group, Le. a sulfonic acid group (SO H) or a saltthereof such as a sodi-osulfo (-4SO3'N8.) group.

In instances where -Q is an aliphatic radical, the sulfo esters arerepresentable by the formula wherein n is an integer, preferably from 2to 4, including instances where C H is a straight chain. Another groupof monomers useful for this component are those disclosed in copendingapplication of William D. Emmons and Graham Swift, Ser. No. 134,905,entitled Sulfonic Acid Monomers and Polymers, filed on Apr. 16, 1971,having the formula (XVIII) X is an aromatic nucleus having 6 to 10carbon atoms or an alkyl group having 2 to 10 carbon atoms, substitutedby a sulfonic acid group and optionally one or more groups selected fromsulfonic acid, carboxylic acid, and lower alkyl, such as methyl, ethyl,propy-l, or butyl.

The proportion of monomeric component (b) in the copolymer may varywidely depending on its hydrocarbon content and also on the content andhydrophobicity of component (a) and of component if any of the latter ispresent, after curing of the copolymer. There may be as little as about0.2% by Weight of monomeric component (b) in the copolymer and there maybe as much as 45% by Weight thereof in the copolymer, particularly whenthe hydrocarbon content or the content of the monomer other thanhydrophilic groups is quite large. However, in most instances, arelatively lower proportion of monomer (b) is present; thus in preferredinstances, there is from about /2 to 8 weight percent of monomericcomponent (b) and the balance of the copolymer units (c) to make 100%,may be composed of vinyl acetate, acrylonitrile, a lower alkyl acry lateor methacrylate in which the alkyl group has 1 to 4 carbon atoms and ispreferably methyl or ethyl acrylate. As part of component (0) there mayalso be used a higher al-kyl acrylate or methacrylate having 5 to 12carbon atoms in the alkyl group in an amount of up to 30% by Weight ofthe copolymer. There may also be present, in an amount of about 0.1 to 5percent by weight, based on the copolymer weight, of one -or moremonomers having a reactive hydrogen atom. Such monomers include thosehaving an amino group in which the nitrogen atom is attached to a carbonatom of a 1,3,5-triazine ring, amido, carboxylic acid, hydroxyl, andmercapto groups, such as acrylamide, methacrylamide, acrylic acid,methacrylic acid, itaconic acid, hydroxyethyl acrylate and mercaptoethylmethacrylate.

Specific examples of monomers of component (b) include:

o-, m-, or p-styrene sulfonic acids o-, m, or p-isopropenylbenzenesulfonic acids o-, m-, or p-alpha-chlorostyrene sulfonic acids o-, m-,or p-alpha-bromostyrene sulfonic acids 2-viny1-3chlorobenzenesulfonicacid 2-vinyl-4bromobenzenesulfonic acid 2-vinyl-5fluorobenzenesulfonicacid 2-vinyl-6-chlorobenzenesulfonic acid 2-bromo-3-vinylbeuzenesulfonicacid 3vinyl-4-chlorobenzenesulfonic acid 3vinyl-S-bromobenzenesulfonicacid 3chloro-4-vinyl benzenesulfonic acid2-fluoro-4-vinylbenzenesulfonic acid 2isopropenyl-3chlorobenzenesulfonicacid 2-bromo-3isopropenylbenzenesulfonic acid3chloro-4-isopropenylbenzenesulfonic acid2-vinyl-3-methylbenzenesulfonic acid 2-vinyl-'4-ethylbenzenesulfonicacid 3isopropenyl-4methylbenzenesulfonic acid3ethyl-4-vinylbenzenesulfonic acid 2-vinyl-3,6-dichlorobenzenesulfonicacid 3vinyl-4-methyl-S-chlorobenzenesulfonic acid1-methoxy-4-sulfo6-vinylnaphthalene 3-isopropenyl-l-naphthalenesulfonicacid 1-sulfo 3,6dichloro-4-vinylnaphthalene Also suitable for use in thepreparation of the new copolymers are those unsaturated aromaticsulfonic acids in which the CH =C group is attached not directly to anuclear carbon, as in the above-listed examples, but to an aliphaticcarbon. Thus, allylbenzenesulfonic acids, methallylbenzenesulfonicacids, and haloallylbenzenesulfonic acids as, for example,

2-allylbenzenesulfonic acid 3beta-methallylbenzenesulfonic acid4-beta-bromallylbenzenesulfonic acid may be used.

Aromatic sulfonic acids in which the sulfonic acid group is attached notto a nuclear carbon but to an aliphatic carbon atom are also suitablefor use according to the present invention, including acids having thegeneral formula in which X may be a halogen atom or an alkyl grouphaving 1 to 4 carbon atoms,

R is hydrogen or methyl or a halogen atom,

Y is a divalent aliphatic, saturated hydrocarbon radical having from 1to 4 carbon atoms,

m is 1 or 2, and

n is zero or a whole number from 1 to 3.

Some examples of such acids are:

Sulfonic acids containing sulfonic acid groups attached both to nuclearand aliphatic carbon atoms may also be used as, for example,1sulfo-3-vinylphenylmethanesu1- fonic acid,

CH=CH SOaH HzSOaH It is preferred to use the aromatic sulfonic acids inthe form of their alkali metal salts for copolymerization. The alkalimetal sulfonate groups in the resinous copolymer product may be readilyhydrolyzed to the free acid by treatment with acid as in the usualprocess for regeneration of exhausted cation exchange resins.

Heterocyclic sulfonic acids containing the necessary CH C group are alsooperative in the preparation of copolymers of the present invention. Afew examples of such acids are:

2-sulfo-5-allylfurane 2-sulfo-4-vinylfurane 2-sulfo-5-vinylthiopheneAliphatic sulfonic acids suitable for use in the present inventioninclude those represented by the general formula in which X may behydrogen or a group such as halogen, carboxyl, sulfo, cyano, carbamyl,nitro, aryl, i.e., phenyl, tolyl, xylyl, naphthyl, etc., saturatedaliphatic hydrocarbon radicals having from 1 to 5 carbon atoms, i.e.,methyl, ethyl, isopropyl, n-butyl, isobutyl, tert. butyl, n-amyl, tert.amyl, and the radicals COOR, COR, CONR2, OR, and RCOO- in which R may beany organic hydrocarbon group, saturated aliphatic or aromatic, but ispreferably an alkyl group of from 1 to 5 carbon atoms; Y is a divalentaliphatic saturated radical of from 1 to 4 carbon atoms, and n is 1 or2.

Thus, there may be used, in addition to ethylenesulfonic acid itself,

l-bromoethylenesulfonic acid l-cyanoethylenesulfonic acid1-carbamylethylenesulfonic acid l-nitroethylenesulfonic acidl-phenylethylenesulfonic acid l-isopropylethylenesulfonic acidl-carbethoxyethylenesulfonic acid 1-carbophenoxyethylenesulfonic acidl-acetylethylenesulfonic acid 1-naphthoylethylenesulfonic acidl-amoxyethylenesulfonic acid 1-biphenyloxyethylenesulfonic acid1-acetoxyethylenesulfonic acid l-benzoxyethylenesulfonic acid2-propenesulfonic acid 3-butenesulfonic acid S-hexenesulfonic acid2-sulfopropene-l 3-sulfobutene-1 2-methyl-4-pentenesulfonic acid3-chloro-3-butenesulfonic acid 2-ethyl-3-butenesulfonic acid Sulfonicacids containing more than a single acid radical, sulfonic or otherwisemay also be used in the preparation of the new copolymers, i.e.

a-sulfoacrylic acid a-sulfoethylenesulfonic acid3-sulfo-4-pentenesulfonic acid 3-vinyl-5-sulfobenzoic acid2-vinyl-1,5-benzenedisulfonic acid 2-vinyl-3-sulfophenylmethanesulfonicacid 3-vinyl-4-sulfomethylbenzoic acid Instead of the sulfonic acids ofthe type disclosed as suitable for use in the present invention,derivatives thereof which are hydrolyzable to the acids may becopolymerized with component (a) and optionally (c) and the copolymerthen hydrolyzed in order to provide free sulfonic acid groups. Alkalimetal salts of the sulfonic acids may be used.

The following are also useful monomers for group 2-sulfoethyl acrylateZ-sulfoethyl methacrylate 2-sulfoethyl a-ethylacrylate 2-sulfoethyla-propylacrylate 2-sulfoethyl a-butylacrylate 2-sulfoethyla-hexylacrylate 2-sulfoethyl a-cyclohexylacrylate 2-sulfoethyla-chloracrylate 2-sulfo-1-propyl acrylate 2-sulfo-1-propyl methacrylate1-sulfo-2-propyl acrylate and methacrylate 2-sulfo-1-butyl acrylate andmethacrylate l-sulfo-Z-butyl acrylate and methacrylate 3-sulfo-2-butylacrylate and methacrylate 2-methyl-2-sulfo-l-propyl acrylate andmethacrylate Z-methyl-1-sulfo-2-propyl acrylate and methacrylate3-bromo-2-sulfo-1-propyl acrylate 3-bromo-1-sulfo-2-propyl acrylate3-chloro-2-sulfo-l-propyl acrylate 3-chloro-l-sulfo-Z-propyl acrylate1-bromo-3-sulfo-2-butyl acrylate l-hromo-Z-sulfo-S-butyl acrylate1-chloro-3-sulfo-2-butyl acrylate 1-chloro-2-sulfo-3-butyl acrylate3-brorno-2-sulfo-1-butyl acrylate 3-bromo-1-sulfo-2-butyl acrylate 103-chloro-2-sulfo-1-butyl acrylate 3-chloro-1-sulfo-2-butyl acrylate1-chloro-Z-methyl-3-sulfo-2-propyl acrylatel-chloro-Z-methyl-2-sulfo-3-propyl acrylate1-chloro-2-(chloromethyl)-3-sulfo-2-propy1 acrylate 1-chloro-2-(chloromethyl) -2-sulfo-3-propyl acrylate 3-methoxy-2-sulfo-l-propylacrylate 3-methoxy-l-sulfo-Z-propyl acrylate 2-sulfocycloheXyl acrylate2-phenyl-2-sulfoethyl acrylate 1-phenyl-2-sulfoethyl acrylate3-sulfo-1-propyl acrylate 3-sulfo-l-butyl acrylate 4-sulfo-1-butylacrylate Ar-sulfophenyl acrylate Ar-sulfophenyl methacrylate 2-(Ar-sulfophenoxy)ethyl acrylate Para-styrene sulfonic acid Ortho-styrenesulfonic acid Para-isopropenyl benzene sulfonic acid Para-vinyl benzylsulfonic acid Ortho-isopropenyl benzyl sulfonic acid Sodium para-styrenesulfonate Potassium Ortho-styrene sulfonate Methyl para-styrenesulfonate Ethyl para-vinyl benzyl sulfonate Ortho vinyl benzene sulfonicacid Isopropyl ortho-isopropenyl benzene sulfonate n-Butyl Ortho-styrenesulfonate Tertiary butyl para-styrene sulfonate 2-chloro-4-vinylbenzenesulfonic acid 4-bromo-2-isopropenyl benzene sulfonic acid 3-vinyltoluene-6-sulfonic acid, sodium salt 2-ethyl-4-vinyl-benzene sulfonicacid 2,3-dichloro-4-vinyl benzene sulfonic acid 2,3,5-tribromo-4-vinylbenzene sulfonic acid 2-chl0ro-3-vinyl-toluene-6-sulfonic acid2,3-diethyl-4-vinyl-benzyl sulfonate, sodium salt Alkenyl sulfonic acidcompounds:

Ethylene sulfonic acid Sodium ethylene sulfonate Potassium ethylenesulfonate Methyl ethylene sulfonate Isopropyl ethylene sulfonateI-propene 3-sulfonic acid l-propene l-sulfonic acid, sodium saltl-propene 2-sulfonic acid, ethyl ester l-butylene 4-sulfonic acid,n-butyl ester l-butylene 3-sulfonic acid Tertiary butylene sulfonic acidSulfoalkylacrylate compounds:

Sulfomethylacrylate Z-sulfoethylacrylate Sulfomethylmethacrylate, sodiumsalt 2-sulfoethylmethacrylate, methyl ester 2-sulfoethylmethacrylate,potassium salt Examples of polymerizable sulfonic acid compounds of theFormula XVIII above include Methacryloxyisopropyl acid sulfophthalateMethacryloxyisopropyl sulfobenzoate Methacryloxyisopropyl acidsulfosuccinate Methacryloxyethyl sulfobenzoate Methacryloxyisopropylsulfopropionate There may also be used styrene disulfonic acid,vinylnaphthalene-sulfonic acid, and B-sulfoethyl vinyl ether.

The sulfonic acid monomer may be polymerized either in its acid form orin the form of a salt of an alkali metal, ammonium hydroxide, or avolatile amine, such as trimethylamine, triethylamine, triethanolamine,diethanolamine, diethylamine, morpholine, and so on. The copolymer maybe in the acid form or it may be fully neutralized or partiallyneutralized by a basic material,

such as any of those mentioned above, and preferably by ammoniumhydroxide, or by sodium, lithium, or potassium hydroxide. The copolymeris preferably in free acid form when used for impregnating a nonwovenfabric so that it serves as its own acidic catalyst for the curingoperation, which then requires only the application of heat such as totemperatures of 50 C. to 150 C. for times of a quarter minute (at thehigher temperatures) to several (3-10) minutes at lower temperatures.

The monomers can be polymerized in conventional ways using, for example,a free-radical catalyst. The polymerization may be effected as asolution polymerization, a suspension polymerization, an emulsionpolymerization, or a precipitation polymerization. Any suitablefree-radical catalyst may be employed, and especially Water-solubletypes when the polymerization is to be effected in aqueous media.Examples include hydrogen peroxide, ammonium persulfate, or an alkalimetal persulfate; a redox system using such a persulfate with a reducingagent such as sodium hydrosulfite. In solution systems involving organicsolvents for the monomers and polymers, a free-radical initiator solublein the particular medium may be employed such as benzoyl peroxide,lauroyl peroxide, tert-butyl peroxide, or hydroperoxide. The usualamounts of initiator may be employed such as from 0.1% to 6% on theweight of the monomer, and in the redox system the persulfate may beemployed in amounts of about 0.05 to 1% or so in conjunction with about0.05 to 1% of sodium hydrosulfite.

Chain-transfer agents and other molecular weight regulators may be used.

NONWOVENS The fibrous webs may be formed in any suitable manner such asby carding, garnetting, or by dry deposition from an air suspension ofthe fibers. The thin web or fleece obtained from a single card may betreated in accordance with the present invention, but generally it isnecessary and desirable to superpose a plurality of such webs to buildup the mat to sutficient thickness for the end use intended,particularly in the making of heat insulation. In building up such amat, alternate layers of carded webs may be disposed with their fiberorientation directions disposed at 60 or 90 angles with respect tointervening layers.

The fibers from which the webs may be made include cellulosic fiberssuch as cotton, rayon, jute, ramie, and linen; also cellulose esterssuch as cellulose acetate; silk, wool, casein, and other proteinaceousfibers; polyesters such as poly-(ethylene glycol terephthalate);polyamides such as nylon; vinyl resin fibers such as the copolymer ofvinyl chloride and vinyl acetate, polymers of acrylonitrile containing70% to 95% by weight of acrylonitrile including those available underthe trademarks Orlon and Acrilan; siliceous fibers such as glass andmineral wools.

An aqueous dispersion of the water-insoluble copolymer of the presentinvention may be applied to the web or mat of fibers in any suitablefashion such as by spraying, dipping, roll-transfer, or the like. Theconcentration may be from to 60% by weight, and preferably from 5% to25%, at the time of application as an aqueous dispersion.

The binder dispersion or powder may be applied to the dry fibers afterthe formation or deposition of the web or mat so as to penetratepartially into or completely through the interior of the fibrousproducts. Alternatively, the binder dispersion or powder may be appliedto the fibers as they fall through the settling chamber to their pointof deposition. This is advantageously obtained by spraying the binderdispersion or powder into the settling chamber at some intermediatepoint between the top and the bottom thereof. By so spraying the fibersas they descend to the point of collection, it is possible to effect athorough distribution of the binder among the fibers before they arecollected into the product. In the production of certain fibrousproducts wherein a hot molten mass of a polymer, such as nylon or afused siliceous mass or glass, is disrupted by jets of heated air orsteam, the binder dispersion or powder may be sprayed directly on thefibers while still hot and very shortly before their deposition so thatquickly after deposition the binder is set and bonds the fibers inproper relationship. Preferably, however, application of the binderdispersion to the fibrous product is made at room temperature tofacilitate cleaning of the apparatus associated with the application ofthe binder dispersion. The binder dispersion may be applied to one orboth surfaces of the fibrous product or it may be distributed throughthe interior as well.

The binder of the present invention may be applied in conjunction withother binders, such as glue. Similarly, the use of potentially adhesivefibers within the fibrous product may also be resorted to in conjunctionwith the use of a binder of the present invention.

If desired, the aqueous dispersion of the polymer and condensate mayalso contain from about /2 to 3% by Weight of a wetting agent to assistpenetration of the fibrous web or mat to which it is applied, and it maycontain either a foaming agent to provide the binder in a foamedcondition in the final product or it may contain a defoamer when theingredients of the aqueous dispersion have a tendency to give rise tofoaming and in a particular case such foaming is undesirable. Theconventional wetting agents, including the alkali metal salts of di(C C)alkyl sulfosuccinic acid, such as the sodium salt ofdioctylsulfosuccinic acid, may be used. The wetting agent may also serveas the emulsifier in preparing the polymer latex or it may be addedafter production of the latex. Conventional foaming and defoaming agentsmay be employed, such as sodium soaps, including sodium oleate forfoaming and octyl alcohol or certain silicones for defoarning.

An acid catalyst may be included in the aqueous dispersion at the timeit is applied to the fibrous web or it may be applied to the fibrous webbefore or after the copolymer is applied. Examples of acidic catalyststhat may be employed include oxalic acid, dichloroacetic acid,para-toluenesulfonic acid, and acidic salts such as ammonium sulfate orchloride and amine salts, such as the hydrochloride of2-methyl-2-aminopropanol-1.

The proportion of the polymer that is applied to the web or mat is suchas to provide 5 to 50% (or, in some cases, even up to by Weight ofcopolymer based on the total weight of copolymer and fibers. Afterapplication of the aqueous dispersion of the water-insoluble copolymerto the fibrous Web, the impregnated or saturated web is dried either atroom temperature or at elevated temperatures. The web is subjected,either after completion of the drying or as the final portion of thedrying stage itself, to a baking or curing operation which may beeffected at a temperature of about 210 to 750 F. for periods which mayrange from about one-half hour at the lower temperature to as low asfive seconds at the upper temperature. The conditions of baking andcuring are controlled so that no appreciable deterioration ordegradation of the fibers or copolymer occurs. Preferably, the curing iseffected at a temperature of 260 to 325 F. for a period of 2 to 10minutes.

It is believed that the curing operation in some way causes reaction ofthe polymer molecules to effect crosslinking thereof to a condition inwhich the binder is highly resistant to laundering and dry-cleaning.This reaction involves the N-methylol groups of some polymer moleculeswith the reactive hydrogen-containing groups of others of the polymermolecules. It is also believed that the curing causes some reactionbetween the N-methylol groups of the polymer molecules and reactivegroups in the fibers such as the hydroxyl groups of the cellulosefibers. While the precise nature of the reaction and the productsthereby obtained are not clearl understood, it is presumed that theresistance to laundering and dry- 13 cleaning is the result of thereaction between binder polymer molecules to cross-link them and/or thereaction between the binder polymer molecules and reactive sites of thefiber molecules. However, it is not intended to limit the invention byany theory of action herein stated.

The bonded fibrous products of the present invention are characterizedby softness, flexibility, resistance to discoloration on exposure toultraviolet light, resistance to chlorinated hydrocarbon dry-cleaningfluids, and resistance to laundering. Because of the softness andflexibility and good draping qualities of the products of the presentinvention, they are particularly well adapted for use in garments whereporosity, especially to moisture vapor, and soft hand and feel, make theproducts advantageous Where contact with the skin of a wearer may beinvolved. In general, the products are quite stable dimensionally andhave good resilience and shape-retention properties. They are adaptedfor use not only in garments but as padding or cushioning, andmoisture-absorbing articles, such as bibs and diapers. They are alsouseful as heatand soundinsulating materials and as filtration media,both for liquids and gases. They can be laminated with paper, textilefabrics, or leather to modify one or both surfaces of the lattermaterials. They may be adhered to films of cellophane, polyethylene,Saran, polyethylene glycol terephthalate (Mylar) or metallic foils, suchas of aluminum, to improve the tear strength of such films and foils, tomake the latter more amenable to stitching, and to modify othercharacteristics including strength, toughness, stiffness, appearance,and handle.

To assist those skilled in the art to practice the present invention,the following modes of operation are suggested by way of illustration,parts and percentages being by weight and the temperatures in degreescentigrade unless otherwise specifically noted.

In the following examples, the tests used with nonwoven fabrics are asfollows:

(a) Absorbency test A sample (4 in. x 4 in.) of the nonwoven is foldedtwice to give a 2 in. x 2 in. square which is thenpassed between steelrollers at 60 p.s.i. A paper clip is attached to weight the sample whichis then placed on the top of a water bath in a beaker at ambienttemperature. The time required by the nonwoven to become saturated isrecorded as the rewet time and the time required for the sample to sinkto the bottom of the beaker is recorded as the sink time.

(b) Tensile strength test A strip 1 in. x 4 in. of each nonwoven is cutin the cross-machine direction, soaked in water, percholorethylene (PCE)or isopropanol (IPA) (each at room temperature) for 30 minutes, and withthe ends of the strip clamped in the jaws of a tensile testing machine,it is then extended to the break.

() Washing Sections of the nonwoven (10 in. x 10 in.) are washed in aconventional home laundry washing machine using terrycloth towels asballast and A cup of the commercial detergent Tide in 16 gals. of Waterat 140 F. using a 34 min. cycle (14 min. wash, 2 min. rinse, 2 min.spin).

(d) Wipe rate test A 4 in. x 4 in. piece of the bonded cotton (about 8oz./yd. or nonwoven (about 0.5 oz./yd. fabric is used to wipe up a 2 ml.water spill on a stainles steel surface. The samples ability to wipe upthe water is rated on a scale of 1 to using the completeness of thewipe, whether a film of water was left or whether beads of water formedon the surface as criteria. A terrycloth towel would rank 1, i.e., thebest, unbonded cotton is ranked 1-2, and if the water is not wiped up atall but smeared into a thin film the rank is 5.

14 (1) A solution of 180 parts sodium vinyl sulfonate (SVS) in 5049parts deionized water is heated to C. A solution of 31.5 parts sodiumpersulfate in 148.5 parts water is added. During a period of 150-160min., while the temperature of the reaction mixture is maintained at81:2 C., the following emulsified mixture is added:

Parts Deionized water 3215.7 Dicapryl sulfosuccinate (Na salt) (60%) in50:50 mix of water and isopropanol 150.3 Methylolated acrylamide soln(50%) 360.0 Ethyl acrylate (EA) 8640.0

NoTm.The methylolated acrylamide is essentially a mixture ofN-methylolacrylamide and acrylamide in about a 1 1 ratio.

At the end of the addition, the mixture is heated to about 85 C. tocomplete the polymerization. Additional initiator may be added tocomplete polymerization if necessary. The product is cooled, filtered toremove small amounts of coagulum, if any, and packaged. The product is amilky-white dispersion of a copolymer of 96% ethyl acrylate, 2% sodiumvinyl sulfonate, about 1.2% N- methylol acrylamide, and about 0.8%acrylamide with the following properties:

Percent T.S 500:0.5 Viscosity cps.. 200:100 pH 2.6103

(2) (a) A viscose nonwoven batt weighing about 0.5 oz./yd. is padded(one dip) through a bath containing 15% polymer solids (obtained bydilution of the dispersion made in (1)) and 0.5% NH CI as catalyst andsqueezed between rolls held with an air pressure of 30 p.s.i. (one nip)to give approximately 150% wet pickup. The saturated webs are air driedand then cured for 3 minutes at 300 F. in a laboratory oven. These websare evaluated for absorbency and tensile strength by the tests describedin (c) and (d) above.

(b) Pieces of cotton of the type used in surgery are also padded (onedip and one nip) through the same bath, air-dried and cured 3 minutes at300 F. and used to evaluate the ability to wipe up a water spill.

(3) Procedure (1) is repeated except that 540 parts of sodium vinylsulfonate and 8187 parts of ethyl acrylate is used and the 60% dicaprylsulfosuccinate is replaced with 60 parts of sodium lauryl sulfate. Theresulting latex is an approximately 51% solids aqueous dispersion of acopolymer of EA, 3% SVS, and about 1% each of acrylamide andmethylolacrylamide.

(4) Procedure (3) is repeated except that the SVS is omitted, the amountof 50% methylolated acrylamide is raised to 720 parts and the amount ofEA is increased to 8540 parts. The resulting approximately 51% solidsdispersion contains a copolymer of 96% EA, about 2%N-methylolacrylamide, and 2% acrylamide.

(5) There is added to the dispersion obtained in (4) about 5 parts, perparts of the dispersion, of dicapryl sulfosuccinate, sodium salt.

(6) Procedure (3) is repeated except that the SVS is omitted, the amountof EA is changed to 8410 parts, the amount of the 50% methylolatedacrylamide is doubled to 720 parts, and 225 parts of itaconic acid (IA)is added. The resulting polymer is a copolymer of 93.5% EA, 2.5% IA,about 2% acrylamide, and about 2% N-methylolacrylamide.

Table I summarizes the results of absorbency tests (a) on the bondedfabrics made according to procedure (2) (a) or (b) with the polymers ofprocedures (1), (3), (4), (5) and 6) before and after washing one ormore times according to wash test (c). It also lists the tensilestrength in ounces per inch width when soaked in water andperchloroethylene (PCE). The table shows that (4), (5), and (6) whichare in effect controls lack the absorbency and/or rewettability of theproducts of (1) and (3) made from copolymer of the present invention.

TABLE I Absorbency (seconds) Wet tensile strength Initial After I washAiter 10 washings Waiter (oz./in.)

w pe

Rewet Sink Rewet Sink Rewet Sink rating H PCE Polymers of (4) and (5)are in eifect controls since they lack component (b) in the copolymerbut are otherwise similar to those of (1) and (3) above. Polymer of (6)shows that use of the weaker carboxylic acid, itaconic acid, cannotproduce the absorbency and wiping characteristics of the copolymers ofthe present invention.

(7) Procedure (1) above is used to prepare an aqueous dispersion of acopolymerof 92% of EA, about 1.6% of acrylamide, about 2.4% ofN-methylol-acrylamide, and 4% of the sodium salt of2-acrylamido-2-methyl-propanesulfonic acid.

(8) Procedure (1) is used to prepare an aqueous dispersion of acopolymer of 92% (EA), about 1% acrylamide, about 1%N-methylolacrylamide and 6% of the sodium salt of methacryloxyisopropylacid sulfophthalate.

(9) Procedure (3) is used to produce an aqueous dispersion of acopolymer of 89% EA, 4% of itaconic acid, about 2% acrylamide, about 2%N-methylolacrylamide, and 3% of the 1:1 mole ratio adduct of butyleneglycol dimethacrylate and sodium bisulfite.

(10) The dispersions obtained in Procedures (7), (8), and (9) are usedto bond a viscose rayon nonwoven as in (2) (a) above and to bond a pieceof surgical cotton in (2)(b) above and then the products are tested withthe results set out in Table II. In this instance, the wet tensilestrength is determined in water and isopropanol (IPA) instead of waterand perchloroethylene.

(14) The procedure of (13) above is repeated replacing the PS5 with 550parts of ammonium acryloxyethyl sulfopropionate (AESP) and the MA with amixture of 600 parts of acrylonitrile (AN), 70 parts of acrylic acid(AA), 4200 parts of MA and 3400 parts of EA, resulting in an aqueousdispersion of a copolymer of about 6.1% AESP, about 6.7% AN, about 0.8%AA, about 1.0% N methylolacrylamide, about 1.0% acrylamide, about 46.6%MA, and 37.8% EA. When the resulting copolymer dispersion is used forbonding a non-Woven fabric or a piece of surgical cotton in accordancewith (2) (a) and (2) (b) hereinabove, the results are similar to thoseobtained with the copolymer of (1) (see Table I).

(15) The procedure of (13) above is repeated replacing the PSS with 880parts of sodium acryloxyethyl o-sulfobenzoate (AESB), and themethylolated acrylamide with 800 parts of a aqueous solution ofN-methylol- 4-pentenoguanamine (MPG), and the MA with 7720 parts EA,resulting in an aqueous dispersion of a copolymer of about 9.8% AESB,4.5% MPG, and 85.7% EA. When the resulting copolymer dispersion is usedfor bonding a non-woven fabric or a piece of surgical cotton inaccordance with (2)(a) and (2)(b) hereinabove, the results are similarto those obtained with the copolymer of (1) (see Table I).

(16) The procedure of (1) above is repeated replacing the SVS with 660parts of the sodium salt of acryloxy- TABLE II Absorbency (seconds) Wettensile strength Initial After 1 Wash After 10 washings Water (oz./in.)

wipe Rewet Sink Rewet Sink Rewet Sink rating H 0 IPA (11) The procedureof (1) above is repeated replacing the SVS with 180 parts of sodiuma-sulf0ethy1acrylate. When the resulting copolymer dispersion is usedfor bonding a nonwoven fabric or a piece of surgical cotton inaccordance with (2)(a) and (2) (b) hereinabove, the results are similarto those obtained with the copolymer of (1) (see Table I).

(12) The procedure of (1) above is repeated replacing the SVS with 450parts of sodium allylsulfonate. When the resulting copolymer dispersionis used for bonding a nonwoven fabric or a piece of surgical cotton inaccordance with (2) (a) and (2) (b) hereinabove, the results are similarto those obtained with the copolymer of (1) (see Table I).

(13) The procedure of (1) above is repeated except the SVS is omitted,320 parts of potassium styrenesulfonate (PS5) is included in theemulsified mixture, and the EA is replaced with 8500 parts of methylacrylate (MA), resulting in an aqueous dispersion of a copolymer ofabout 94.5% MA, about 3.5% PS8, about 1% of N- methylolacrylamide, andabout 1% of acrylamide. When the resulting copolymer dispersion is usedfor bonding a nonwoven fabric or a piece of surgical cotton inaccordance with (2)(a) and (2) (b) hereinabove, the results are similarto those obtained with the copolymer of (1) (see Table I).

ethyl acid 3,5-disulfophthalate (AEDSP), the methylolated acrylamidewith 260 parts of N-methylol-B-ureidoethyl acrylate (MUA), and the EAwith a mixture of 7600 parts of EA and 480 parts of fi-hydroxyethylacrylate (HEMA), resulting in an aqueous dispersion of a copolymer ofabout 7.3% AEDSP, 2.9% MUA, 5.3% HEMA, and 84.5% EA. When the resultingcopolymer dispersion is used for bonding a nonwoven fabric or a piece ofsurgical cotton in accordance with (2)(a) and (2) (b) hereinabove, theresults are similar to those obtained with the copolymer of (1) (seeTable I).

(17) The procedure of (1) above is repeated replacing the SVS with 810parts of the sodium salt of 8-acryloxyoctyl acid 3,5-disulfophthalate(AODP), the methylolated acrylarnide with 360 parts of an aqueoussolution containing parts of N-methylolmethacrylamide and parts ofN-methylol-4-pentenamide (MPA), and the EA with a mixture of 3600 partsof isopropyl acrylate (iPA) and 4400 parts of MA, resulting in anaqueous dispersion of a copolymer of about 9% AODP, about 0.9%N-methylolmethacrylamide, about 1.1% MPA, 40% iPA, and 49.0% MA. Whenthe resulting copolymer dispersion is used for bonding a nonwoven fabricor a piece of surgical cotton in accordance with (2)(a) and (2)(b)hereinabove, the results are similar to those obtained with thecopolymer of (1) (see Table I).

(18) The procedure of (1) above is repeated replacing the SVS with 1000parts of the ammonium salt of acryloxyethoxyethoxyethyl a c i d 4sulfophthalate (AE3EOSP), the methylolated acrylamide with 400 parts ofan aqueous solution containing 50 parts of N-methylolallylguanamine(AMG) and 150 parts of N-methoxymethyl-4-pentenoguanamine (MOMPG) andthe EA with a mixture of 4600 parts of propyl acrylate (PA) and 3300parts of EA, resulting in an aqueous dispersion of a copolymer of about11% AO3EOSP, 0.5% MAG, 1.6% MOMPG, 50.5% PA, and 36.4% EA. When theresulting copolymer dispersion is used for bonding a nonwoven fabric ora piece of surgical cotton in accordance with (2) (a) and (2) (b)hereinabove, the results are similar to those obtained with thecopolymer of (1) (see Table I).

(19) Procedure (3) is repeated except that the sodium lauryl sulfate isreplaced with 150 parts of sodium diocytl sulfosuccinate (60% in a 50:50mixture of water and isopropanol) A portion of the resulting latex isused to bond a nonwoven fabric and cotton wadding by Procedures (2)(a)and (b) with results similar to those obtained with polymer (3) as shownin Table I.

(20) Procedure (1) is repeated except that the SVS is replaced by 210parts of 2-acrylamido-2-methyl-3-butanesufonic acid and the surfactantsolution is replaced with 130 parts of a 50% solution in a 50:50 mix ofwater and isopropanol of the sodium salt of di-dodecyl sulfosuccinate.

A portion of the resulting latex is used to bond a nonwoven fabric andcotton wadding by Procedures (2)(a) and (b) with results similar tothose obtained with polymer (3) as shown in Table I.

We claim:

1. As an article of manufacture, a nonwoven fabric bonded by at least 5%by weight, based on the weight of fibers in the fabric, of a copolymerof (a) 0.2 to by weight of at least one c p-monoethylenicallyunsaturated monomer containing an amino group in which the nitrogen atomis attached to a carbon atom of a 1,3,5-triazine ring, a carboxylamidegroup, or a ureido group, the nitrogen atom of such amino,carboxylamido, or ureido group being substituted by a methylol ormethoxymethyl group, (b) 0.2 to 11% by weight of at least oneafi-ITIOHO- ethylenically unsaturated monomer, in acid or salt form,having a sulfur-containing acid group and containing no basic nitrogenatom and (c) the balance to make 100% by weight, of at least one otheru,,B-monoethylenically unsaturated monomer which contains nosulfur-containing acid group, or salt thereof, and no basic nitrogenatom.

2. As an article of manufacture, a nonwoven fabric according to claim 1wherein the copolymer comprises from about 0.5 to 4% by weight ofmonomeric material (a), and from about 0.5 to 8% by weight of monomericmaterial (b).

3. A nonwoven fabric according to claim 1 wherein the 20 fabric isformed of cotton or rayon fibers.

4. A nonwoven fabric according to claim 2 wherein the fabric is formedof cotton or rayon fibers.

References Cited UNITED STATES PATENTS WILLIAM D. MARTIN, PrimaryExaminer T. G. DAVIS, Assistant Examiner US. Cl. X.R.

117-143 A, 145, 161 UN, 161 UZ, 161 UT

